docs: def cancel_firewall(self, firewall_id, dedicated=False):
          """Cancels the specified firewall.
  
          :param int firewall_id: Firewall ID to be cancelled.
          :param bool dedicated: If true, the firewall instance is dedicated,
                                 otherwise, the firewall instance is shared.
          """
  
          fwl_billing = self._get_fwl_billing_item(firewall_id, dedicated)
          billing_item_service = self.client['Billing_Item']
          return billing_item_service.cancelService(id=fwl_billing['id'])